Molding press



' Momma rams v Filed June 7, 1940 A 2 Sheets-Sheet 1 IN NTORS FORREST.DAIWES ATTOR E Y ES Oqt. 5,1943. F. L. DAwEs ET AL 2,331,015

MOLDING PRE'ss 1 Filed June 7, 1940 2 Sheets-Sheet 2 INVENTOR5 FORRESTL. DA was 40 0 m? H. 57' nrrolv BY 7 5 A TORNEYS Patented Oct. 5, 1943MOLDING PRESS Forrest L. Dawes, Kent, and Edgar H. Stratton,

Cuyahoga Falls, Ohio, assignors'to The Adamson Machine Company, Akron,Ohio, a corporation of Ohio Application June 7, 1940, Serial No. 339,334

6 Claims.

which mold sections are adapted to mate with complemental mold sectionscarried by a stationary upper platen secured to the upper head of thepress, and a movable lower platen secured to the lower press'head on theram of the press. In such presses it frequently happens that the workbeing molded adheres to the mold sections with such tenacity as toretard separation thereof as the press ram is lowered, with the resultthat the intermediate platen or the lower platen does Referring to thedrawings, there is shown a j hydraulically operated molding presscomprising bottom thereof.

not descend with the ram. Thus the subsequent separation of themoldsections allows the said platens to drop, frequently with resultingdamage a to themselves or to other parts of the press.

It is to the relief of this condition that this invention primarily isdirected.

The chief objects of the invention are to provide in an improvedmannerfor efiecting the separation of the molds and platens in a moldingpress of the character mentioned; to obviate damage arisin when molds donot separate as,

the press vis opened; and to provide a single mechanism arranged toeffect concurrent separation of two molds in a molding press employingan intermediate or floating platen. Other objects will be manifest asthe description proceeds.

Of the accompanying drawings:

Figure 1 is a front elevation of a molding press embodying theinvention, in the open position of the press, parts being broken awayand in section;

Figure 2 is a side elevation of the press in the open position thereofshown in Fig. 1;

Figure 3 is a sectional detail, on a larger scale, of one of the pair ofdevices employed for separating the press molds, the press parts beingshown in closed position;

Figure 4 is a view of the structure shown in Fig. 3, as it appears inoperation, while the press is opening; and

Figure 5 is a section, on a larger scale, on the line 5-5 of Fig. 2.

a base in to the opposite sides of which are secured upstanding strainplates H, II that support an upper press head H2 at the top thereof. Thebase 10 is formed interiorly with a cylinder chamber I3 that has avertical axis and which receives a ram ll, fluid for operating thelatter being delivered to the cylinder and evacuated therefrom through apipe i5 at the The usual packing gland l6 surrounds the ram where itemerges from the cylinder l3. Resting upon the top of the ram I4 is thelower press head I! that is provided at its four corners with guideplates, such as the guide plate l8, Fig. 1, that slidably engagereespective corners of the strain plates H for preventing angular movementof the press head I! relatively of the ram [4. The press head I! carriesa lower platen i9 that is separated from said head by a layer of thermalinsulation 20 interp'osed therebetween. 'In like manner an upper pressplaten 2i is secured to the downwardly presented face of the upper presshead l2 over an interposed layer of thermal insulation 22. Positionedintermediate the said upper and lower platens is a floating platen 23which, in the open position of the press, rests upon narrow ledges orsupporting plates 24, 24, Fig. 2, that are attached to the confrontingfaces of the strain plates II. The four corners of the platen 23 areprovided with respective uide plates 25 that slidably engage adjacentcorners of the strain plates H to prevent angular movement of theplaten. The platens I9, 2| 'and 23 are shown as solid plates, but theymay be formed interiorly with passages for receiving hot or cold fluidif desired.

The press is equipped with two molds of which 21, 21 are mating sectionsof the lower mold secured to the lower platen I9 and intermediate platen23 respectively, and 28, 28 .are mating sections of the upper moldsecured to the inter mediate platen 23 and upper platen 2| respectively.Said platens may be of any suitable size and shape and are formed withthe usual cavities (not shown) in which articles are molded. All.

of the foregoing structure is of well known construction and no noveltyis claimed for it per se.

Each of the strain plates H is centrally formed with a vertical slot 30extending substantially from the base I 0 to the upper press head l2,and

positioned in said slots are respective mold separating devices,designated as a whole by the numeral 3!, which devices are carried bythe interi by respective retainer plates 341s formed interlorly with anaxial chamber 36 that extends from'end uniform diameter throughout, andmounted in said chamber are two pistons 31, 31, each of which isprovided with suitable packing their cylinders 34,

portions located in The outer end of each piston 31 is above the same.

loadingpurposes,

.separating devices are in the it the lower press mediate platen 23 thisend said platen 23 is formed at each side with laterally extendingprojections 32 that extend through the respective slots 30 in the strainplates ll, said projections being recessed at 33 inwardly from the outerfaces thereof to receive respective fluid pressure operated cylinders 34that are disposed on vertical axes. Y are circumferentially their endsso as to overlie the marginal portions The latter grooved midway between01' said recesses, and are secured in said recesses 35. Each cylinder toend thereof and is of ample, a plurality of piston rings 38, 38 asshown, that prevent the passage of fluid between the pistons and thechamber wall. The pistons 31 are adapted to be projected outwardly bypressure fluid, preferably hydraulic, that is discharged into chamber 36through a central port 39, said port being connected to an inlet andoutlet pipe 4D.;.- The latter may be a flexible hose, but preferably ithas a swingable extensible connection I? with a suitable source ofpressure fluid (not shown).

The pistons 31 have limited axial movement in and to this end eachpiston is formed with a diametric slot 42 that extends longitudinallythereof. Extending through each of stud or pin 43 that has its end adiametric bore in the cylinder 34, the respective ends of said borebeing closed by plugs 44, Fig. 2, threaded thereinto. formed with a 45in which is mounted a 46 that is retained in said said slots 42 is ashallow axial recess projecting wear-pin bore by a set screw 41, Fig. 3.The arrangement makes the wear-pin readily replaceable if it shouldbecome chipped or broken during use, and obviates the necessity ofreplacing the entire piston. Furthermore, wear-pins of different lengthsmay be provided so that the mold separating devices willfunction'normally notwithstanding molds of various thicknesses that maybe employedwith the press.

The pistons 310i each cylinder 34 are arranged to operate against astrain plate I I and the lower press head I1 respectively. To this endeach strain plate is formed, at the top of its slot 30,

with an integral outwardly projecting lug 50 that extends across theprojected axis of a cylinder 34, Alsothe lower press head I1 as shown isintegrally formed, on opposite sides thereof, with laterally extendingbrackets 5| that project through the slots 30 of the respective strainplates II and extend across the projected axis of the respectivecylinders 34, below the same. If desired, the brackets 5! may beseparate elements that are bolted or otherwise secured to the presshead.

The operation of the improved press is as follows. Normally there is nofluid pressure in the cylinders 34, and when the press is open, as

shown means, for ex- 7 at opposite sides thereof. To

upwardly in the cylinders 34, but before the lower ends of the pistonslots &2 meet their cross-pins 43, the lower mold section 21 meets itsmating section 21 to close the mold, whereupon rising movement of theintermediate or floating platen 23 begins, which platen lifts with itthe cylinders 34. The platen 23 continues to rise until the moldsections 28 move into mating relation, which position of the variousparts of the press is shown in Fig. 3. It will be noted that in theclosed position of the press, the upper pistons 3? are supported ontheir pins 43, but that the wear-pins 46 of the upper pistons are not incontact with the lugs 53 on the strain plates it, so that said pins 53are required to support only the weight of the pistons, and no otherstrain The press remains in closed position until the work in the molds21 and 2B is fully molded, and subjected to heating or cooling if themolding process includes such treatment.

Thereafter, the press is opened, this being effected by evacuating ordischarging of the pressure fluid in the ram cylinder 93. Concurrentlywith the discharging of the cylinder 13, the cylinders 34 of the moldseparating devices are charged, with the result that the pistons 31thereof are projected outwardly in opposite directions, the upperpistons exerting pressure against the lugs 50 of the strain plates toassure separation of the upper mold. sections 28 and consequent descentof the floating platen 23, and the lower pistons 31 exerting pressureagainst the lower press head i1, through the agency of its brackets 50,to assure separation of the lower mold sections 21 and consequentdescent of the said lower press head with the ram. The arrangement issuch as toinitiate the separation of the three platens, and to supportthe intermediate platen midway between the upper and lower platens untilthe pistons 31 of the cylinders are fully projected. The floating platencontinues to descend until it comes to rest upon the supporting plates24, the lower platen continuing to descend until the ram 14 reaches thebottom of its stroke, which is the position shown in Figs. 1 and 2. Itwill be clearly evident from said figures that the pistons 31 are out ofcontact with the lugs 50 and brackets 5| well before the floating platenreaches its supporting plates 24 and before the lower platen reaches itsfully lowered position, the arrangement being such that the pistons 31impose no strain upon the lugs 50 or upon the brackets 5| after thefloating platen has traversed but a part of its descending course, andat no time impose any strain upon the supporting plates 24. i Thecylinders 34 may then be evacuated. This completes a cycle of operationwhich may be repeated as desired.

In an alternative method of operation, the cylinders 34 are charged atall times, usually from the same source that supplies fluid to thecylinder 13, but in the closing of the press, because of the greaterarea of the ram M, the pretons 31 are forced into their cylinders 34,against the pressure of the fluid therein, said fluid being forced backinto the supply line. Thus upon evacuation of the cylinder l3, thepressure in cylinders 34 automatically functions to effect separation ofthe mold sections in the press as described.

The invention is relatively simple in construction,its cost 'ofconstruction and operation is low, it assures positively the separationof the molds in the press as the latter opens, and it is imposed onthem.

achieves the other objects set going statement of objects.

out in the forecomprising opposed platens, means for moving said platenstoward each other to close the press, and a fluid pressure cylinderdisposed between said platens, including a pair of pistons in saidcylinder so positioned as to be movable in opposite directions intooperative engagement with said platens to initiate separation of theplatens during the opening of the press, the cylinder and pistons beingso constructed that the combined movement of the pistons .is less thanthe extent oi separation of the platens whereby. the latter areseparated from the pistons when the press is fully open. a

2. A molding press of the character described comprising a plurality ofplatens including an intermediate platen, means for moving said platenstoward each other to close the press, and a fluid pressure cylindermounted upon an intermediate platen including a pair of pistons in saidcylinder adapted to be projected in opposite directions into engagementwith respective platens above and below said intermediate platen toinitiate separation of the platens during the opening of the press, themovement o1v the pistons in the cylinder being less than the extent ofseparation 01' the platens when the press is fully open whereby the withsaid pistons.

3. A molding press of the characterdescribed comprising a stationaryhead, a head movable 3 toward said stationary head to close the press, afloating platen disposed intermediate said heads, and a fluid pressurecylinder carried solely by said platen including in said cylinder inposition to engage a stationary structure and said movable headrespectively after the press is closed and prior to the opening thereofto initiate separation of the said heads from said platen during theopening of the press, said pistons being of such length as to stand inspaced relation to said heads when the press is fully open,

platens are out of engagement 4, A molding press of the characterdescribed A comprising a plurality of platens including .a platenintermediate two platens, means for moving said platens toward eachother to close the press, and a fluid pressure cylinder mounted solelyupon the intermediate platen for initiating separation of the platensduring the opening of the press, said cylinder comprising an axialchamber, a pair of pistons projecting from opposite ends of said chamberin position to engage the platens at opposite sides of the intermediateplaten, and means limiting the axial movement 01' said pistons in .bothdirections to a distance that is lessthan the distance between adjacentplatens in the fully open position of the press.

5. A combination as defined in claim 4 in which the means for limitingthe axial movement of the pistons consists of pins secured in thecylinder and extending through diametric slots in the pistons.

'6. A combination as defined in claim 4 including renewable wear-pins inthe outer ends of the respective pistons.

FORREST L. DAWES. EDGAR H. STRA'IION.

a pair of opposed pistons

